Butchers notoriously miss this change of direction in address (10)
I believe the answer is:
apostrophe
'address' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for apostrophe that I've seen before include "Mark showing omission of letters" , "Passage addressed to character" , "Mark in exam's" , "Sign of omission" , "It may be superfluous on tradesman's sign" .)